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authorWillem de Bruijn <willemb@google.com>2018-11-24 14:21:16 -0500
committerDavid S. Miller <davem@davemloft.net>2018-11-24 17:42:57 -0800
commitaba36930a35e7f1fe1319b203f25c05d6c119936 (patch)
treedc960b49f6616419375e9fec056022c0e8e14338 /net
parent9efdda4e3abed13f0903b7b6e4d4c2102019440a (diff)
net: always initialize pagedlen
In ip packet generation, pagedlen is initialized for each skb at the start of the loop in __ip(6)_append_data, before label alloc_new_skb. Depending on compiler options, code can be generated that jumps to this label, triggering use of an an uninitialized variable. In practice, at -O2, the generated code moves the initialization below the label. But the code should not rely on that for correctness. Fixes: 15e36f5b8e98 ("udp: paged allocation with gso") Signed-off-by: Willem de Bruijn <willemb@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
-rw-r--r--net/ipv4/ip_output.c3
-rw-r--r--net/ipv6/ip6_output.c3
2 files changed, 4 insertions, 2 deletions
diff --git a/net/ipv4/ip_output.c b/net/ipv4/ip_output.c
index c09219e7f230..5dbec21856f4 100644
--- a/net/ipv4/ip_output.c
+++ b/net/ipv4/ip_output.c
@@ -939,7 +939,7 @@ static int __ip_append_data(struct sock *sk,
unsigned int fraglen;
unsigned int fraggap;
unsigned int alloclen;
- unsigned int pagedlen = 0;
+ unsigned int pagedlen;
struct sk_buff *skb_prev;
alloc_new_skb:
skb_prev = skb;
@@ -956,6 +956,7 @@ alloc_new_skb:
if (datalen > mtu - fragheaderlen)
datalen = maxfraglen - fragheaderlen;
fraglen = datalen + fragheaderlen;
+ pagedlen = 0;
if ((flags & MSG_MORE) &&
!(rt->dst.dev->features&NETIF_F_SG))
diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c
index 89e0d5118afe..827a3f5ff3bb 100644
--- a/net/ipv6/ip6_output.c
+++ b/net/ipv6/ip6_output.c
@@ -1354,7 +1354,7 @@ emsgsize:
unsigned int fraglen;
unsigned int fraggap;
unsigned int alloclen;
- unsigned int pagedlen = 0;
+ unsigned int pagedlen;
alloc_new_skb:
/* There's no room in the current skb */
if (skb)
@@ -1378,6 +1378,7 @@ alloc_new_skb:
if (datalen > (cork->length <= mtu && !(cork->flags & IPCORK_ALLFRAG) ? mtu : maxfraglen) - fragheaderlen)
datalen = maxfraglen - fragheaderlen - rt->dst.trailer_len;
fraglen = datalen + fragheaderlen;
+ pagedlen = 0;
if ((flags & MSG_MORE) &&
!(rt->dst.dev->features&NETIF_F_SG))